pDCs express S1P receptors, and FTY720 treatment causes accumulation of pDCs in LNs with a corresponding decrease of pDCs in the blood. (A) T cells, B cells, and pDCs were sorted from LNs and spleens of C57Bl/6 mice. The expression of S1Ps1-5 was determined by quantitative real-time PCR. For the first 3 graphs, the amount of S1P1 mRNA was set as 1, and the value of S1P4 mRNA expression was expressed as relative amount compared with the S1P1 value. For the fourth graph, the amount of S1P4 mRNA in T cells was set as 1, and the value of S1P4 mRNA expression in other cell subsets was expressed as relative amount compared with T cells. Data from 1 of 3 independent experiments are shown. (B) C57Bl/6 mice were treated with FTY720 intravenously. After 18 hours, blood and LNs were assessed for B cells, T cells, and pDCs by flow cytometry. Lymphocyte and pDC numbers calculated per 1 mL blood and in 6 harvested LNs (2 inguinal, 2 axillary, 2 brachial) from 3 independent experiments are shown. *P < .05; **P < .005.